LAOS CARAVAN Training

Case Study29 Nov 2005

Watershed Management

Objective:Discuss watershed management aspect based on soil erosionLand cover/use extraction, DEM creation, soil erosion and GIS analysis planning support for plannerCapacity building for local staffs on the use of GIS and Remote Sensing for watershed management

Study area

NamNgum watershedNamNgum Dam have two main upstream as show in figure.Case study was based on the watershed loacted at of the Dam.

DATA

RS and GIS data

RS data

LandsatPath 128 Row 47 27 Dec 1999

JERS OPSPath 124 Row 269 27 Dec 1995Path 124 Row 269 30 Oct 1996Path 124 Row 269 24 Apr 1997

GIS Data

LayersLand use 1993 and 1997River networkRoad networkVillages with population data (spreadsheet)ContourProvince boundary andDistrict boundary

Using RS & GIS

• Update landuse

• Extract watershed boundary

• Create terrain data: elevation, surface

• Generate the drainage network

• Evaluate the soil erosion in watershed area

• Carry out Spatial analysis

Hands-On Content

Introduction ArcGIS and Data Creation/HandlingLanduse Classification:Visual Screen EditingWatershed ExtractionGIS Analysis

3 D analyst and Spatial AnalystApplying Parameters

Landuse, Slope and TransportationCase study area extraction

Introduction ArcView

Data Creation/Handling

I. Overview of Arcview Software

-Double Click -Or click at Start Menu

1

5

2 3

84

6 9

7

1. Application Window

2. Menu Bar

3. Button Bar

4. Tool Bar

5. Project Window

6. View Window

7. Layout Window

8. Chart Window

9. Table

1.1 Arcview Components

1.2 Graphical User Interface (GUI) for View

Zoom Full Extent

Zoom Active Extent

Zoom Select Extent

Zoom InOpen Theme Property Table Zoom Out

Previous ZoomTheme Properties

Clear Selected FeatureAdd a Theme

HelpPointer or Selector

Identify the feature

Different GUIs for different windowsTableProject

View Layout

1.3 Format of ArcView Data

•Data Layer is called Theme in ArcView•One theme in ArcView will have at least 3 physical files with extension

*.dbf (table data)*.shp (spatial data)*.shx (relations)

District.shpDistrict.dbf (table data)District.shp (spatial data)District.shx (relations)

1.4 Themes

Active/NonActive

Legends

Theme has properties as

Visible/Invisible

1.5 Data Display and Overlay

Add theme or themes Check box to visible a theme: district.shpDouble click on theme for legend display: district.shpSelect Legend type: Unique ValueValues Field: DnameArrange for theme order: drag and drop

1.6 Layout for printing map

•Activate View window•Select View\Layout…•Select one paper style on Landscape Manager (portrait or landscape)•Choose <New Layout>, Try edit with objects on the layout.

1.7 Extension of ArcView•Activate the project windows•Select File\Extension•Select extension program (Geoprocessing)•Extension program will occur in menu, button or tools in individual interface (View Windows, menu View\Geoprocessing)•Try with another extension, Spatial Analysis and 3D Analysis

Extension of ArcView

Spatial Analysis3D Analysis

Landuse Classification

Visual Screen Editing

Steps

Landuse 1997RegroupOverlay with Landsat image Update landuse

Landuse 1997

Add theme “Landuse_fcm9397”

Look up table Landuse codeAdd Table “mrc_fclc_type” (Forest/Land cover type )

Join attribute table

Open attribute table

of “Landuse_fcm9397”

Click field name

“Fclc_code” in

“mrc_fclc_type” table

Click field name “F97” in

“Landuse_fcm9397”

table

Press Join button

Display Landuse type

In Legend editor, change

Value Field as “Type”

Click Apply button and change Symbol color

Re-class Landuse typeIn order to make the landuse class to simply landuse classes, the landuse type can be group into forest and other landuse

Forest

Edit table / Add fieldStart Editing table, add new field, Set field definitionThen query [Type] = “forest”

Input new re-group landuse

Copy Type “Forest” into “Reg_lu97”field using calculator button

Click switch selection button select the remaining landuse type

Copy other landuse into “Reg_lu97” field click [Reg_lu97] = [Fclc] in calculator tool

Stop Editing

When finish.

Display new re-class landuseChange color in Legend Editor according to new re-classed landuse (Field “Reg_lu97”)

Open image and compare with landuseAdd image theme name “Tm_p128r47_9912b432.tiff” and “Tm_p128r47_9912b321.tiff”

Edit/Update Landuse theme

• Convert landuseTo new file name• Change legend color and Start Editing in Theme menu

Using Edit Feature Tool

• Use Vertex Edit tool or Draw Line to Split Polygon tool•Edit attribute table for landuse type•Save and Stop Editing when finish

Watershed Extraction

How to defined watershed boundary?

From which data WS can extract

Stream Network

Hydrologic

SRTM-DEM

GIS data-RiverSatellite Image

SRTM-DEM STREM Network

How can defined Watershed?

1) Boundary between rivers or river systems

2) Range between valleys or long depressions in the surface of the land

3) Major river catchments should be covered

Add Data Layers

• Add GIS layers and satellite imageries (river_utm48.shp, srtm_stream.shp,

p128r047_7t19991227_z48_nn123_subset.tiff and srtm_u03_p128r047sub.tif)

Create New Layer

5) Select New Theme in View Menu to create new GIS layers, Select select the polygon features in pop-up windows

6) Then guide to the folder where new data file have to store and give name as watershed.shp

7) The watershed.shp file will be appear in the theme list

8) Use Draw Polygon Tool to digitize on screen to create watershed polygon

Watershed Boundary

GIS analysis and Parameters

3 D Analyst and Spatial AnalystLanduse

1997

SlopeContour

TransportationRoad and Stream

GIS analysis

LanduseLayer

ContourLayer

Convert to GRID

TIN Surfacing

Giving Scores

Giving Scores

Converted to GRID

+

Giving Scores

Output GRID

Derive SLOPE

LANDUSE ⊕ SLOPE LANDUSE ⊗ SLOPE

*

Giving Scores

Transportation layer

Convert to GRID

Buffering

+*

Transportation

Case Study Area

Clipping with WS

LANDUSE and Population

Soil Erosion MAP

ArcView GIS Analysis

There are two main ArcView GIS Analyst software extensions will be used in this case study.They are:1. 3 D Analyst2. Spatial Analyst

3 D Analyst

Support for 3D shapes, surface modeling, and real-time perspective viewing to ArcView.

3D shape - store z coordinates, in addition to x and y, for every point used to define a feature.Two types of surface models are available - grids and triangulated irregular networks (TINs).3D Scene Document provides an interactive viewer that puts your data in a new perspective.

Spatial Analyst

The main component of the Spatial Analyst is the grid theme. The grid theme is the raster equivalent of the feature theme.The Spatial Analyst also presents generic spatial analysis functionality on grid and feature themes.Main available function are: Find Distance, Assign Proximity, Calculate Density, Cell Statistics, Summarize Zones, Histogram By Zone, Tabulate Areas, Map Query, Map Calculator, Neighborhood Statistics, Reclassify, Interpolate Grid, Create Contour, Derive Slope, Derive Aspect, Compute Hillshade, Calculate Viewshed, Convert to Shapefile (not added, but modified to work with grid themes), Convert to Grid, Save Data Set, Edit Theme Expression, Manage Data Sources, Import Data Source, Export Data Source

Semi-quantitative method Parameters

ParametersLanduse

Slope and

Transportation

LANDUSE Parameter

LanduseLayer

Convert to GRID

Giving Scores

Scoring Landuse Parameter

Defined four scores based on forest typesScore 0 has no erosion potential such as water body, wetland, RockScore 1 has less erosion potential such as evergreen/deciduous forest, Score 2 has high erosion potential such as Grassland, Shrub and Urban, low cover forestScore 3 has very high erosion potential such as barren land, agriculture land

Erosion Experts can be defined with his/her experience on landcover/landuse

Landuse 1997

Forest Types

NO Reclass (Score) Code Name

1 0 93 Rocks2 0 95 Water3 0 96 Wetland4 1 11 Evergreen, high cover density5 1 12 Evergreen, medium - low cover density6 1 17 Mixed (evergreen and deciduous), high cover density7 1 18 Mixed (evergreen and deciduous) medium - low cover density8 1 40 Regrowth9 2 13 Evergreen mosaic10 2 19 Mixed mosaic11 2 61 Wood- and shrub land, evergreen12 2 62 Grassland13 2 94 Urban or built-over area14 3 81 Cropping mosaic, cropping area <30%15 3 82 Cropping mosaic, cropping area >30%16 3 92 Barren land

Landuse Scoring

Converted -Landuse layers to Grid with pixel size 30ReclassificationScore Landuse type

0 = 96, 95, 931 = 11, 12, 17, 18, 402 = 13, 19, 61, 62, 943 = 81, 82, 91, 92

Find erosion values from internet

Landuse 1997 Grid conversion

Landuse GRID

Landuse GRID

Scoring Landuse 1997

CONTOUR Parameter

ContourLayer

Convert GRID

Giving Scores

TIN Surface

Derive SLOPE

Scoring Slope Parameter

Defined four scores based on slope degreeIf the slope is 0° - 7°, we defined score 1 and has Less erosion potentialIf the slope is 7° - 15°, we defined score 2 has medium erosion potentialIf the slope is > 15°, we defined score 3 has high erosion potential

Score can adjust based on regional elevation.In this case study, area is mostly undulated land.

Select layers for Slope Scoring

•Road Network

•River Network

•Contour

Create TIN from Contour

TIN (Triangulated Irregular Network)

TIN partitions a surface into a set of contiguous, non-overlapping, triangles. A height value is recorded for each triangle node. Heights between nodes can be interpolated thus allowing for the definition of a continuous surface.

TIN to GRID

GRID from Contour

Drive Slope from GRID

Slope

Scoring Slope

Score Slope Arable Land

Slight Slope degree < 7 degrees; slight erosion of water, existence of soil A layer & improvement

Medium Slope degree 7-15; Loss of soil A layer, gully process

Severe Slope degree >15, serious gully process

Scoring Slope Grid

Scores of Slope

Logically way of Thought

Landuse

Score 0

Score 1

Score 2

Score 3

Slope

Score 1

Score 2

Score 3

Slope ⊕ Landuse

Score 1

Score 2

Score 3

Score 4

Score 5

Score 6

Slope & Landuse

Slope ⊕ Landuse

Logically way of Thought

Slope ⊗ LanduseScore 0Score 1Score 2Score 3Score 4

Score 6

Score 9

Landuse

Score 0

Score 1

Score 2

Score 3

Slope

Score 1

Score 2

Score 3

Slope & Landuse

Slope ⊗ Landuse

Comparison Adding and Multiplying

TRANSPORTATION Parameter

River and Road

Convert GRID

Giving Scores

Buffering features

Scoring Transportation Parameter

Defined four scores based on how far from Transportation Route (River and Road)

Score 1 has very less erosion potential areas where the places located within 4 Kilometers far from Transportation routeScore 2 has less erosion potential areas where the places located within 3 Kilometers far from Transportation routeScore 3 has high erosion potential areas where the places located within 2 Kilometers far from Transportation routeScore 4 has very high erosion potential where the places located within 1 Kilometers far from Transportation route

Transportation

Included Road network and River network

Merged Layers

Road layer and River layer

Buffering

How far People can walk?

Buffering

Buffer extended to two sides

Intersecting with Boundary

Intersecting with Boundary

Transportation Scoring

Score Buffered distance1 = 3 to 4 Kilometers2 = 2 to 3 Kilometers3 = 1 to 2 Kilometers4 = Feature to 1 Kilometers

Converted GRID with Scores

Landuse ⊕ Slope ⊕ Transportation

Landuse ⊕ Slope ⊕ Transportation

Landuse ⊗ Slope ⊗ Transportation

Landuse ⊗ Slope ⊗ Transportation

Overlaid Watershed

1 km Buffered Watershed

Raster to Vector

Raster to Vector

Extracting Case study area

Extracting Case study area

Semi-Quantitative Watershed by Adding

Semi-Quantitative Watershed by Multiplying